package com.jspservletcookbook;
import java.io.PrintWriter;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
public class BlockFilter implements Filter {
private FilterConfig config;
/** Creates new BlockFilter */
public BlockFilter() {}
public void init(FilterConfig filterConfig) throws ServletException{
this.config = filterConfig;
}
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = null;
boolean authenticated = false;
PrintWriter out = null;
if (request instanceof HttpServletRequest){
req = (HttpServletRequest) request;
String user = req.getParameter("user");
authenticated = authenticateUser(user);
}
if (authenticated){
chain.doFilter(request,response);
} else {
response.setContentType("text/html");
out = response.getWriter();
out.println("<html><head><title>Authentication Response</title></head><body>");
out.println("<h2>Sorry your authentication attempt failed</h2>");
out.println("</body></html>");
out.close();
}
}// doFilter
public void destroy(){
/*called before the Filter instance is removed
from service by the web container*/
}
private boolean authenticateUser(String userName){
//authenticate the user using JNDI and a database, for instance
return false;
}
}
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